Listen

It's the easiest act of kindness you can do, besides smile.
The next time someone converses with you or perhaps confides in you, listen. Make sure that the conversation is truly about them. Do not start your sentence with "Well I would.." or "In my experiences.." or anything that really just pertains to you. After having many conversations like these where the person thinks they're helping me by telling me about THEIR lives and stories, I've learned to be a better listener. Most of the time, people really don't want black and white advice. They need time to vent and some sympathy. A good listener will be able to tell what message a person is trying to convey by picking up on emotional and physical cues. It's simple, just pay attention and stop thinking about your laundry list of things to do today.
It's just one more way of putting someone else before yourself.